docs: def _update_offset_file(self):
          """
          Update the offset file with the current inode and offset.
          """
          if self.on_update:
              self.on_update()
          offset = self._filehandle().tell()
          inode = stat(self.filename).st_ino
          fh = open(self._offset_file, "w")
          fh.write("%s\n%s\n" % (inode, offset))
          fh.close()
          self._since_update = 0